1. Field of the Invention
This invention pertains to oil and/or gas wireline wells and specifically to a means of controlling/containing pollution that may occur during the operation of the wireline wellhead.
2. General Background
In wireline wellheads, as the braided wire, cable, rope, or electric conductor enters or leaves the wellhead, it is quite common for a considerable amount of grease, oil, lubricants, toxins, or other contaminants to become attached to and then drip or otherwise come off the wireline, the top sheave and/or related apparatus. This may occur whether the well is pressurized or not and these unrestrained pollutants can eventually find their way into nearby water and/or soil. Additionally, these pollutants, by their nature, are slippery and can thus pose a risk to nearby workers since this material can spill onto stairwells, hand railing, and other nearby equipment and/or structures which are frequented by workers.
Some attempts to retain pollutants within wireline wells include the use of pack offs and/or oil strippers in non-pressurized wells. These devices strip the contaminants off the wireline as it is pulled out of the well. Additionally, there are grease injectors which pump grease or other high viscosity material into pressurized wells so as to maintain pressure therein. These grease injectors are typically used in conjunction with the aforesaid pack offs and/or oil strippers in order to restrain such contaminants within the well. Some such devices are described as follows.
U.S. Pat. No. 5,150,751 issued to Burton, et al., discloses one attempt to contain such pollutants by enclosing the uppermost region of a stuffing box of a well. Thus, any pollutants spilling out of the stuffing box, such as due to the packing therein becoming dried, worn, or damaged, will collect in the enclosure and be transported elsewhere. However, by only enclosing the uppermost region of the stuffing box, only pollutants from this region will be contained. Additionally, even though the wireline or cable passes through this enclosure, no means are disclosed to scrape or remove pollutants from this wireline or cable. Consequently, the contaminated wireline or cable will leave the enclosure thereby dripping and discharging such pollutants outside the enclosure.
U.S. Pat. No. 4,530,397 issued to Calhoun discloses an apparatus that is secured to the upper region of a stuffing box of a polished rod oil well pump. It is used to contain any oil leakage should the packing in the stuffing box become worn or dry out. This apparatus relies upon scraping such oil off the polished rod and does not take into consideration any oil that may drip down the polished rod nor is this apparatus applicable to wirelines since a wireline involves much more flexibility and degree of movement than a solid polished rod.
U.S. Pat. No. 5,211,227 issued to Anderson discloses a fugitive emission accumulator which is secured atop a stuffing box for capturing oil at the wellhead and returning it back to the well. This apparatus operates by wiping the fugitive oil from the emerging polish rod.
U.S. Pat. No. 4,665,976 issued to Retherford discloses a deflector shield assembly for use with a well pump incorporating a polished rod. This shield seals entirely around the stuffing box and the polished rod and serves the purpose of passively retaining any oil that may leak from the well.
U.S. Pat. No. 4,951,743 issued to Henderson discloses a flexible leakage protector, or bellows, that fits around the polished rod. As the polished rod reciprocates within the well, the bellows encloses such rod thereby preventing any leakage from occurring.
U.S. Pat. No. 3,322,198 issued to McHenry discloses a safety hood for installation around a wellhead or bonnet. This safety hood incorporates an opening in its upper region for the passage therethrough of a polished rod. Should a leak occur, such leakage will be contained within the hood. No steps are taken to actively stop any contaminant from escaping via the polished rod.
U.S. Pat. Nos. 3,186,722 and 3,270,810 both issued to Johnston discloses a wellhead enclosure with an upper flexible bellows surrounding a polished rod. Thus, as the polished rod reciprocates, it remains enclosed within the bellows.
U.S. Pat. No. 3,500,907 issued to Gentry discloses a closed or self-contained system whereby both the upper and lower lubricator sections are each secured to a separately located tank. The purpose of this system is to clean wireline tools without permitting toxins to escape into the atmosphere.
While each of the above disclose attempts at containing and/or cleaning wellhead tools, they primarily operate passively, i.e. they contain a leak should one arise rather than actively attempting to remove oil and gas from the components of a well that extend beyond the wellhead. Furthermore, those devices which do attempt to wipe oil off the polished rod before exposing it to the atmosphere, are not capable of similar operation with a wireline due to the greater flexibility and less rigidity of the wireline with respect to the polished rod and also the greater degree or angle of movement allowed by the wireline as compared to a polished rod. Additionally, these devices themselves become saturated and/or covered with contaminants thereby compromising their ability to retain such contaminants within the well. Also, the upper or top sheave that normally is suspended above these devices also becomes covered and saturated with pollutants thereby discharging same into the environment. Further, should the pressure control device (i.e., the grease injector assembly) experience a loss of pressure, a large volume of contaminants can spill or leak out under such pressure.
It is thus an object of this invention to provide a means of containing/controlling spills arising from a wireline wellhead, whether pressurized or not. Another object of this invention is to provide a means of allowing for the flexibility of the wireline while still providing for the cleaning of the wireline. Yet another object of this invention is to surround the stuffing box and top sieve so as to provide a means of containment should a leak occur or should there be an unexpected pressure release. Still another object of this invention is to enable the user to continue to use whatever containment devices are already installed on the wellhead. These and other objects and advantages will become obvious upon further investigation.